The surveillance system is widely used in various applications, such as fire detection, police surveillance, coast surveillance, environmental protection, military surveillance, aero-traffic, medical service, and various public safety situations. The modem surveillance system incorporates computers, communication, and satellites to provide a close surveillance and protection. As the price of the hardware reduces in recent years, the surveillance system is also adopted in more business settings, offices, and households. For example, the surveillance system can be set up to monitor the safe, business venue, warehouse, high-priced goods, production line, and so on. The surveillance system can even be set up in the neighborhood to prevent theft, burglary, vandalism, or littering.
However, most of the conventional surveillance systems use a chain-connected or star-connected master/slave structure. For example, U.S. Patent Application Publication 2003/0050989 A1 disclosed an audio data transmission system using a digital communication network, such as Ethernet, to connect a master module and a plurality of slave modules in a chain or a star topology, as shown in FIG. 1. Although this type of topology allows data transmission and system monitoring, it lacks in fault-tolerance. Once a communication segment between two stations is out of order, the communication between these two stations is cut off. Another drawback of such type of topology is that the communication delay is large, especially for the stations at the end of the communication chain. This also affects the system efficiency.
As the hardware price continues to decrease and the surveillance is more widely adopted in different venues, it is imperative to provide a more effective surveillance system to overcome the above drawbacks.